Braking apparatus



M. LOUGHEAD BRAKING APPARATUS 1. ,2 9. .l A" ...u c O VOriginal Filed Deo.17. 1920 INZENTOR l ('dl 1mb -wnb (m A ToRNEY vRaiatea oa. 4, 1927.

i' UNITED STATES i' PATENT oFF1cE.'-

MALCOLM LOUGHEAD, 0F DETROIT, MICHIGAN, ASSIGN'OR, BY MESNE ASSIGNMENTS, n

T HYDRAULIC BRAKE COMPANY, 0F LOS ANGELES, CALIFORNIA, ACORPORATION 0F CALIFORNIA.

BEARING APPARATUS.

Original No. 1,495,231, dated May 27, 1924, Serial No. 431,334, led December 17, 1920.l Application for l reissue led March 28, 1925. Serial No; 19,180.

M invention relates to braking apparatus of t e fluid-operated type for automobiles and similar vehicles, and is concerned especially with improvements in a fluid compression device adapted for use in connection with apparatus of the kind mentioned which is operated by a foot pedal or other means for supplying fluid under pressure to the brake operating mechanism.

One of the objects of the resent invention resides iii the provision o pressure producing mechanism ofthe character described by means of which the fluid column is manipulated throughout the braking operation, without causing a suction in the system which might efect the introduction ofA air bubbles at leaks occurring in the line, which would seriously impair the general effectiveness of the pressure mechanism.

Another object of m invention consists in the provision of a mec anism of the .character described, which comprises a fluid reservoir for relieving any suction which may be sating for leakage at joints throughout the system whereby a constant supply of operating Huid is maintained in the system.

A still further object resides in the provision of an improved compression device wherein simultaneously operable high and low pressure producing means are provided.

A still further object resides' inthe provision of means controlled by the pressure inv the system for disassociating the low pressure producing means from. the system.

The foregoing and other objects of the present invention will appear as the followino' detailed description progresses, in which re erence is made tothe accompanyingdrawing, wherein Figure'l is a skeleton plan of a. braking system of the character described applied to an automobile, in connection with which myV improved Huid compression device is adapted to operate.

Figure 2 is a longitudinal vertical section of the device of my invention, the parts thereof being illustrated in their respective normal inoperative positions,'and

Figure 3 is an isolated end view of the -re-filling valve forming an element of the device shown in Figure 2.

roduced in the, system, and for compen' The same reference numerals designate the same parts throughout the views.

Referring to the drawing, the compression device of my invention is designated generally by the 'reference numeral 4, and is and a similar pair of'braking mechanisms 5 on the rear wheels of the automobile.`

pipe running the length of the chassis which supplies the communicating branches at the adapted to operate a pair of braking mechanisms 5--5, on the forward steering wheels,

front and rear of the chassis, preferablyv through swivel connections shown at 4-4". While these connections maybe of anysuitable design and construction, I prefer to provide connections as illustrated in my application, Serial No. 431,335, filed of even date herewith.

Referring now particularly to Figure 2, it will be noted that my improved compression device comprises amain casting .6, having an upwardly extending bracket 7 formed integral therewith. Provided near the upper end of the bracket is an integral, laterally projecting lug 8, which is securely held in a clamping collar provided on the bracket 9. The bracket 9 is bolted or otherwise supported conveniently on the nether side of the toe board 10, which, as illustrated, extends at an angle of substantially 45 to the floor 11. While the device is illustrated as tilted at an angle of substanf' lf2.. Y

i tendpand -slidably receives' apiston 15, whichprojects a substantial distance above the toe board 10, andl is provided at its outer end with a suitablefoot pedal 16. The piston 15 is provided with a concentric bore 17, which is closed at its upper end at the dal 16 byv means of a plug 18, and atits ower end has a downward] working cup leather 19, secured thereto suitable bushin 20.

Slidable int e bore 17, and the piston 15, which IA shall hereinafter refer -to yas the Ylow pressure piston is ,a second iston .21', which will hereinafter be referre to as the high pressure piston.l The piston 21 is fixed in relationto Vthe cylinder 12 and is provided'with a'longitudina'l concentric bore 22, the upper end of which is slightly-reduced to provide a shoulder 23. Secured to this -end of the piston 21, by means of a rin'gl 24, is an upwardly working cu leather'25. The endsanged as shown to en.

of the .ring 24 are gage at one end the shoulder 23, and at the other end the 'cup leather 25. -The iston 21 is enlarged at its lower end-as s own, and is threaded' into the lower end of the bore 14- of the cylinder 12. Aplug 26l closes the lower end of the bore 14 shghtly beneath the lower end of the piston 21, to rovide a substantial chamber 27, withiw 'ch the'bore 22 communicates. vThe lower end of the cylinder bore14 is enlargedas shown to provide'a chamber 28 .above the enlarged lower end of the iston 21. e

A shoulder 29 is provided on the cylinder- 12 and a tension` spring -30 surrounds the cylinder 12' and piston 15, and lies between the shoulder 29, and the pedal 16,r tending to 'ur e the piston l15 outwardly.v from the cylincrl A` longitudinal slot 31 prov vlded in the outer wall of the piston 15 cooperates: with a set screw 32 to4 limit the reciprocal movement of. they the cylinder 12.

' Formed integral with the castinigf'and parallel to the cylinder 12 are Ithe cylinders 33 fand 34.` Provided ad'a'cent the ends of the4 cylinder 33 are the va ve seats 35 an'dl'36,

The valves 37 and 38 are rovided with stems 39 which .are thread Y 40 wherebv the stems Iare secured tothe valves. )The opposite enlarged bifurcated ends 41 of the stems 39 are joined by means of a1ink42 as'sh'own. vIt 'will be seen that the valves 37 v and are-'so coupledxthat when one of them #is seated, the other is open. The open'end of the cylinder 33is closed by a threaded plug 43. An adjustin screw 44 extends through the plug 43,` and carries on itsinner end a collar 45,-to pro' erly tension-.the sprin 46, which urges t e valve 37 toits seat.` o prevent leakage of y meansof av co-axial with pheric pressure.

f piston f within to co-operate valvesv f at their outer; ends to' receive nuts conditions. The spring 56 is very havingv s uicient tension .merely to hold the `v .valve 55to its` seat.

fluid under rassure past the screw"44,pack

ing materia 47 is provided which may be suitably compressed by anut 48.

The opposite end of the cylinder 33 is provided with a nipple 49 with which the outlet pipe 50 is connected.by means of'a union 51. Thepipe 50 may be joined with the pressure responsive means of the brake operating mechanism in any desired manner but preferably as disclosed in my application, Serial No. 431,332 above mentioned.

A transverse passage 52 establishes comby a. threaded plug v55. A tension springL 56 is .disposed between the plug 55 andthe valve 54, tending' to holdk the latter `to its seat. v f u s The end ofthe cylinder'34 opposite the plug 55 is provided with an `externally- .threaded stem 57 which is prfo'vided withia central bore 58 opening into; the cylinder 34. Connected to the stem 57 by means of a union 59 is a" pipe 60 which extends upwardly to a uidreservoir 65 which may be. located upon the rear of vthe instrument boardor anly other' convenient place. The .interior of t e reservoir is subject to iatmos- A passage 61 extends .transversely in the casting 6vover Vthe passage 52 and parallel therewith, "and establishes .communication between the chamber 28 at the.. lower end of the cylinderf12and the cylinder 33 between valves 37 and 38,;and the cylinder'34, be-V neath the rellingvalve 54. Another passage 62 .joins the cylinders 33 and 34 at their,I upper ends.

In order tol lpermit easy steady movement 'n 'of the valves v37, 38 and 54 within their .Are-

spect-ive cylinders,.and in ordernot to,l'1n- :duly impede the passage of luid thereby,

I preferably vform these valves with uted ortions 63,`ben'eath the heads as most cleary Aseen'in Fi rc3, and as a further precaution I provi e openings as shown at 64, be-' tween the webs of the-fluted portion 63, ad-

jacent the valve head.

i Before proceeding to a description of the operationof the mechanism just described,

-it may be noted that the spring 46 which tends to lforce the valve 37 Vto its seat2 has 'preferably a tension suicient to reslst a pressure' of approximately 20 pounds per square inch.-v However, -the`spr1ng tension maybe widely varied yto accommodate 'A v,rarer entire device is, of xlzo'urse, complete# ly lled with the operating flu1d=.wh1ch 1 s preferably a non-compressible oiloralcoholj althou h a compressible luid asvair may" be utilized. The fluid reservoir65 previously mentioned is filled almost com letely periodicall to compensate for the'` oss of oil throng out the system, due-to leakage', evaporation, etc. l

When the parts are in their. respective normalinoperative positions, the piston is substantially withdrawn from the cylinder 12,'"and the valves 37 and 54 are closed;

the valve 38, however, being open. Pressure upon the pedal 16, communicated thereto byY the operators foot, depresses the p1ston 15,

which causes a flow of oil from the space about the piston 21 through passage 61, past the valve 38, intothe pipe 50, and, simul taneously from the bore 17 through passa e 52, also into t-he ipe 50. pression of the pe al 16 causes the flow of oil along this circuit until'all of the slack is taken up in the brake bands by the brake operating. mechanism above referred' to. I

have found that at this point the. pressure in subjected to atmospheric the system has reached approximately 20 pounds. The moment this tained, and depression -of t e pedal16 1s continued, the valve 37 is unseated against the tension of the spring 46. Simultaneously,fwith the o ening of valve 37, the'v valve 38 isclosed. e space above the valve 37 is connected to the reservoir 65 which is ressure. The fluid under pressure 1n the cy nder 33 rushes past the head of the valve, thereby urging the same upwardly and assisting the valve 38 tol seat quickly. Furthermore, the pressure beneath the valve 38, assists the very prom t closing of this valve and holds it close as long as the pressure is maintained.

-As the depression of the pedal 16 is continued, a very great increase of pressure in the system results, since the same is subject solely to the pressure produced by the high pressure piston, the bore of which, it will-be noted, is very small, to permit a. broader range of movement of the pedal and at the same time to permit of a greater range of production of pressure in the system. Si-

multaneously .with the Aproduction of the high pressure in the pipe by the high pressure piston, the low pressure piston is causing a ilow of oil through the passage 61 past the valve 37 through passage 62 into cylinder 34, o ut through the pipe and up- .wardly into the fluidv reservoir 65.- By-the time thelow pressure piston reaches the vicinity of the chamber l2 8 the pressure existing in thev system pro ucedby the high pressure piston is very high, so high', in fact, that I have found I am enabled to stop a vehicle in a muchv shorter distance than it has heretofore been possible. VWhen it is de- Continued eressure 1s at-r sired to relieve the braking pressure in the removes his system, the operator simplg/ foot from the pedal16. As't ere is'nomeasin the system, it is .necessary to provide spring. means at various oints to insure the easy and rapid return'o the parts to vtheir vvurable amount of compression in the fluid respective normal linoperative positions. In

this connection the spring '30 is provided to ur ethe edal 16 outwardly. A rather con-f si erable ead is produced by' the luidwhich has been forced into the -fluid ireservoirb theY low pressure piston, as above describe As the low' pressure piston recedes,}-this `fluid is returned to the system through the reiilling valve 54 which is, unseated by .the great'- er pressure existing on the up r side thereof. When the pressure in t e system has been reduced to approximately 20 pounds per square inch, the valve 37 will be urged to its seat, thereby opening the valve 38. As the loycr ressure piston recedes' further,

fluid assmg through the passalge 61 past the va v e 38 and passage V52 into t e chamber 27 andthence into the bore v22 completely fills the opening in the bore 17 above the highl pressure piston. In a llike manner, lluid passing the valve 38 into the passage` 6l and past the refilling valve 54 into-pas' sage Gland thence'into the.bore 14 ofthe 54 5, i. .v cylinder .12 completely fills the annular space beneath the lowpress'ure piston. The

turn to their normal inoperative positions; .the refilling valve'54 being urged to its seat sides of this valve.

-parts fare, in this manner, permitted to re- 1 ioo b v the spring 56, the'moment a difference of pressure `no longer exists on opposite .In the foregoing description, I have made 'use of the terms innen outer`, upper,

lower etc. which, it must be understood, are used merely in their relative sense and not in their speciicsense. v

While I have described the details of the preferred vembodiment of my invention, I do not limit myself to these specim'details. but claimv further all adaptations and scope of the appended claims."

What I claim is:

modifications coming within the spirit and members, a. fluid pressure system, means responsive to the pressure therein' for operating sald brake members, and` means for creating pressure in said system comprising a high pressure producing means, a low pressure producing means, an outlet for the fluid under pressure to said means automatically actuated upon the fluid being subjected to a predetermined pressure for closing communication between said outlet and said low pressure lproducing means.

2. In a braking system for vehicles, brake .los

.1to1l 1115 1'. In a braking system for vehicles, brake system, and' y members, a uid pressure system, means re- 13 sponsive to the pressure therein for. operating said brake members, means for providingfluid under pressure, an outlet for the fluid under pressure, said pressure providing means comprising a highpressure producing means ontinually in communication with said outlet, a low pressure producing v means normally in communicationwith said 3. In a braking system for vehicles, brake members, a fluid' pressure system, means responsive to the pressure therein for operating said brake members, means for providing fluid under pressure, an outlet for the fluid under' pressure, said ressure providing means comprising a hig pressure producing means arranged to force a small volume of fluid into said outlet under `high pressure, a low pressure producing means arranged to force a large volume of fluid into said system underr low pressure, said high and low pressure producing meansbeing arranged to botli force fluid into said outlet upon initial operation, and means operable at a predetermined pressure produced in said outlet for closing communieation between said outlet and said low pressure producing means.

4. In a braking system `for vehicles, brake members, a fluid pressure system, means responsive to the pressure therein lfor operating said brake members, and means for creating pressure in said system comprising a high pressure producing means, a low ressure producing means, an outlet for the uid under pressure, said low pressure producing means being normally in communi cation with said outlet, said high and-low pressure producin means being arranged upon initial operation to both force fluid into said outlet, and valves operable at a predetermined pressure produced in 'said outlet for closing communication lbetween said out- `let and said low pressure producing means,

but maintaining communication between said high pressure producing means and said outlet. f

5. In abraking system for vehicles, brake members, sponsive to the pressure therein for operating said brake members, means for providing fluid under pressure, an outlet for the Huid under pressure,sai d pressure providing means comprising means .for initially injecting a large volume of fluid into said outlet under low pressure, means operable only at a predetermined pressure produced in' said outlet for closing communication between said outlet and said means for initially in- ]ecting, and means for thereafter injecting ytween said outlet and said low a fluid pressure system, means remembers, a fluid pressure system, means responsive to the pressure therein kfor operat- 'l ing saidbrake members, means for provid` ing fluid under pressure, an outlet for said fluid yunderpressure, said pressure providing means comprising a high pressure pro- 1 ducing means arranged for forcing a large volume of fluid into said outlet under aY high pressure, a low pressure producing means arranged to force a relativel large lvolume of fluid linto. said outlet un er a comparatively low pressure, a fluid reservoir, said high and low pressure producing means being arranged upon 'initial operation to both force fluid into said outlet, means operated by a predetermined .pressure produced in said outlet for closing communication bepressure produc-ing means and placing said low pressure producing means in communication with said fluid reservoir, whereby said high pressure producing means is alone maintained in communication4 with said outlet, and means operable upon reduction of pressure in said outlet for providing communication between said reservoir and said high and low pressure producing means whereby fluid from said reservoir is caused to reenter the pressure producing means.

7. In a braking system :tor vehicles, brake members, a fluid pressure system, means re` sponsive to the pressure therein for operating said brake members, and means for creating pressure in said system comprising Vahigh pressure producing meaiis, a low pressure producing means, an outlet for the fluid under ressure, said high and low pressure pro ucing means being arranged upon initial operation to both force fluid into said outlet, a fluid reservoir, and means actuated by a predetermined pressure in said outlet for closing communication between said low pressure producing means and said outlet and opening communication between said low pressure producing means and said fluid reservoir.

8. In a braking system for vehicles, brake members, a fluid pressure system, means responsive to the pressure therein for operating said brake members',y means for 4providing a fluid under pressure, an outlet for the fluid under pressure,l said pressure providing means comprising a high pressure cylinder arranged to have constant communication with said outlet, a low pressure cylinder arranged to normally have communicationwith said outlet, pistons in said cylinders, a fluidl reservoir, means for causing relative movement of said pistons and cylinders, means, operable at .a predetermined pressure produced in said system for opening communication between said uid reservoir and said low pressure cylinder and or between the fluid reservoir and said outletV to establish communication between said reservoir and said high and low pressure cylinders for replenishing the supply lof iuid iin said cylinders after operation.

9. In .a braking system for vehicles, brake members, a iiuid pressure system, means responsive to the pressure therein for operating said brake members, means for roviding iuid under pressure, an outlet or said fluid under pressure, said pressure providin means comprising a high pressure cylin er arranged to have constant communication with said outlet, a low pressure cylinder arranged to normally have communication with said outlet, pistons in said cylinders, meansl for causing said pistons to enter said cylinders simultaneously to force the'fiuid from said cylinders, a fluid reservoir, a pair of valves controlled by the pressure in said outlet, said valves being so arran ed that when one is seated the other is oil' its seat, one of said valves serving to establish communication between the said low pressure cylinder and said fluid reservoir, the other of said valves serving to limit the communication ofthe high pressure cylinder to said outlet.

10. In a braking system for vehicles, brake members for engaging the brake drums of the wheels, a fluid pressure system and means responsive to the pressure therein for operating-said brake members, a device for creatin pressure in said system comprising a 'gh pressure producing means, a low pressure producing means an means responsivey to predetermined pressures in said system for opening and closin communication betweensaid system and said low pressure producing means.

1l. In a braking system for vehicles, brake members for en aging the brake drums of the wheels, a uid pressure system and means responsive to the pressure therein for operating said brake members, a device for creating pressure in said system comprising a high. pressure producing means continually in communication with said system, a low pressure producing means normally in communication with said system, and means operable at a predetermined pressure in said system for cuttin oii' said low pressure producing means rom communication with lsaid system.

12. In a braking system for vehicles, brake members for en aging the brake drums of the wheels, a uid pressure system and means responsive to the pressure therein for operating said brake members, a device for creatinl pressure in said system comprising a 'gh pressurepproducing means arranged to force a small volume of fluid into saidv system, under high pressure, a low pressure producing means arranged to force a'large volume' of fluid into said system underlow Vressure, said high ,and low pressure pro ucing means being arranged upon initiall operation to both force fluid into said system, and a pair of mechanically con,-` nected valves operable at a predetermined pressure in said system for closin communi-v cation betweeii said system an said low pressure producing means, and limiting communication of the high pressure producing means to said system.

13. In a braking system for vehicles, brake members for engaging the brake drums of the wheels, a fluid pressure system and means responsive yto ythe pressure -therein for operating said brake members,-

a device for creating pressure in said system comprisin means for initially injecting a large vo ume of fiuid into said system, means o erableby a predetermined pressure in sai system for closing communi'- cation between said system and said firstmentioned means, and means for thereafter in]ecting a small volume of fluid under lhigh pressure into said system.

14. In a braking system for vehicles, brake members for engaging the `brake drums of the wheels, a fluid pressure system and means responsive to the .pressure therein for operating said brake members, a device for creatin pressure in said system comprisin a high pressure producin means arrange to force a small volume o Huid into said system under a high pressure, a low pressure producing means arranged to force a comparatively large volume of uid into said system under a relatively low pressure, said high and low pressure producing means bein arranged upon initial operation to both orce uid into said sysvtem, a fluid reservoir, means operable by a predetermined pressure produced in said system for closing communication between said system and said low pressure producing means and opening communication between said low pressure producing means and said f'luid reservoir, whereby said high pressure producing means is alone maintained in communication with said system and means operable upon the reduction of pressure in said system for establishing communication between said fluid reservoir and said high and low pressure producing means, whereby fiuid from said reservoir re-enters said pressure producing means to replenish the supply of iuid therein.

415. In a braking. system for vehicles, brake members, a Huid pressure system,- means responsive to the pressure therein for izo in the space between said first-mentioned cylinder and said piston member` and itself forming a piston, fluid within all the openings and spaces within the said cylinders and' piston, means for causing movement of sa1d second cylinder relative to said firstmentioned cylinder and piston member carried thereby, whereby said fluid is forced from said cylinders under pressure, an outlet for said fluid, a passage continually connecting said opening to said outlet, a Second passage normally connecting said space to sald outlet and means operated by a predetermined pressure in said passages and said outlet for closing the connection of said second passage to sai-d outlet. 'f

16. In a braking system for vehicles, brake Amembers, a fluid pressure system, means responsive tothe pressure therein for operating said brake members, and means for creating pressure in said system, comprising a cylinder, a piston member within said cylinder spaced therefrom and secured thereto, said piston member having an opening, extending longitudinally thereof, a second cylinder arranged to slide in the space between said first-mentioned cylinder and said piston member and itself forming a piston, fluid within all the openings and spaces within the. said cylinders and piston, means for causing movement of said second cylmder relative to said first-mentioned cylinder and iston member carried thereby, whereby sai fluid is forced from said cylinders under pressure, anoutlet for said Huid, a passage continually connecting said openin to said outlet, a second passage normal y connecting said. space to said outlet, a fluid-reservoir and means operated by a lpredetermined pressure in sald passages and said outlet for closing the connection of said passage to said outlet, and joining said' second passage to said fluid reservoir.

17..In a braking system for vehicles, brake members, a luld pressure system, means responsive to the pressure therein lfor operating said brake members, and means for creating pressure in said system comprising a cylinder, a piston member within said cylinder spaced therefrom and secured thereto, said piston member being provided with an openin extending longitudinally thereof, a secon cylinder arranged to slide in "the space between said first-mentioned cylinder and said piston member and itself forming a piston, fluid within lall the openings and'spaces within the said cylinders and pistons, means for causing movement of lsaid last-mentioned cylinder relative to said first mentioned cylinder and piston member carried thereby, whereby said fluid is forced from said cylinders under pressure, an outlet for said fluid, a passage continually connecting said opening to said outlet,r a second passage normally connecting said space to said outlet, a Huid reservoir, and a pair of valves operated by a predetermined pressure in said passages and said outlet for closing the connection of said second passage to said outlet, and joining it to said fluid reservoir.

18. In a braking system for vehicles, brake members, a fluid pressure system, means responsive to the pressure therein for operating said brake members, and means for creating pressure in said system comprising a cylinder a piston member. concentrically arranged withinv said cylinder spaced therefrom and secured thereto said pistonmember being provided with an opening extending longitudinally thereof, a second cylinder arranged to slide in the annular space between said first-mentioned cylinder and said piston member and itself forming a piston, fluid within all the o enings and spaces within the said cylin ers and pistons, means for causing movement of said second c linder relative to said rst mentioned cylmder and piston member carried thereby, whereby said fluid is forced from said' cylinders under pressure, an outlet for said fluid, a passage continually connecting said opening to said outlet, a second passage normally connecting said annular space to said outlet, a uid reservoir, and a pair of valves operated by a predetermined pressure in sald passages and said outlet for closing the connection of said sec- `ond passage to said outlet and joining it to said fluid reservoir.

19. In a braking system for vehicles, brake members for engaging the brake drums of the wheels, a Huid pressure'system, means responsive to the pressure therein for operatingsaid brake members, a device for creatin pressure in said system comprising a high vpressure producin means, a low pressure producing means, an a valve for opening and closing communication between said system and said low pressure producing means, said valve being actuated responsive to changes inl pressure above and belowa predetermined pressure in the system. y

20. A hydraulic braking's stem comprising hydraulically actuated brake-applying wheel cylinders, a liquid reservoir, a compressor including 'a master cylinder communicating with the wheel cylinders, retractile means therefor, operatin independently of the backpressure from t e wheel cylinders to replenish said master" cylinder from the reservoir by suction, and valve means interposed between the compressor and the wheel cylinders for preventing a complete relief of the positive pressure in the Wheel cylinders. c

21. A hydraulic braking s stem comprising hydraulically actuated rake-applying wheel cylinders, retractile means therefor tending to create a positive pressure on the liquid therein, a liquid reservoir, a compresf sor including a master cylinder ycommunicating with the wheel cylinders, retractile means therefor operating independently of the back pressure from the wheel cylinders to replenish the master cylinder from the reservoir by suction, and valve means interposed between the master cylinder and the wheel cylinders for'preventlng said suction on the former from relieving the positive back pressure in the latter.

.In .witness whereof, I'hereunto subscribe my name this 23rd day of March, 1925.

MALCOLM -LoUGHEAn 

